Two piece cowl grills such as disclosed in U.S. Pat. No. 4,679,845 are connected at a tongue and groove connection that is adjustable to change the length of the cowl so as take into consideration differences in the lateral distance between connection points on a vehicle resulting from manufacturing tolerances. While suitable for its intended purpose the cowl arrangement in the '845 patent depends upon a groove shaped elastomeric seal that fits around the lower edge of a windshield to seal the gap between the cowl and the windshield. The groove shaped seal provides a friction-type lock against lateral shifting between the windshield and the cowl after the cowl has been connected to the vehicle and the windshield has been installed to the cowl. While suitable for use on windshield arrangements that require a bottom edge seal it lacks the flexibility of positioning required in windshield/cowl gap seal systems wherein the gap is sealed by a seal element that includes a flap that seals against the windshield at a point above the lower edge thereof.